Bolton Gate Composite sliding fire doors are approved for up to four hours fire resistance in accordance with BS 476 Part 22 1987 and are also approved by Factory Mutual. Their flushfaced appearance and slimline construction makes them an ideal solution to openings where headroom restrictions prohibit other types of door. They can be designed to blend in with the surrounding structure or even used as a feature due to their versatility of panel designs - stainless steel and factory finished door leaves are available.